Copper alloy for chill and die casting



Patented Apr. 10, 1934 UNITED STATES PATENT OFFICE,

corraa armor roa emu. m ins cas'rmo Elgenvaderl, Eberswalde, Germany No Drawing. Application May 29, 1830, Serial No. 457,546. In March 31, 193.

1 Claim.

, My invention relates to a copper alloy for chill and die casting. It is an object of my invention to improve an alloy of this type, and to this end I admlx silicon thereto.

5 Chill and die castings are manufactured to a limited extent only, and by preference of copperzinc alloys, aluminium brass and aluminium Another drawback of aluminium bronze is the high shrinkage. Castings having recesses and cavities often become welded at the-cores so that it is diiiicult or even impossible to extract the cores. When a core sticks-the alloy must be the permanent mould which is very detrimental to the mould.

Die castings of brass lack strength and their faces are rough on account of the zinc vapour 26 formation. Parts undergoing high stress, such as gearwheels, cams, bearing brasses, etc., cannot be die cast from brass as the brass does not possess the properties required for such parts.

0n the other hand, copper-silicon alloys are 30 equally suitable for chill and for die casting. The

favorable influence of silicon is two-fold. Firstwith.

ly, it improves the mechanical properties of the castings and gives them a perfectly smooth surface. due to the formation of silicon dioxide. A surface of such smoothness will not be attained with any of the existing alloys. Secondly, silicon is a good deoxidizing agent so that the castings are free from slag, which further improves the surface.

Preferably, zinc is added to the copper-silicon alloy, as the mechanical properties are much improved by such addition.

A suitable alloy has the following composition:

Percent Copper to 94 7o Silicon 6 to 2 Zinc 28 to 3 If it is desired that the alloy should have particular properties, for instance, should be suit able'as a bearing metal, other metals are added but not exceeding 2%.

Such metals are: lead, antimony, bismuth, cadmium, tin, nickel, cobalt, manganese, iron, chromium, aluminium, titanium, tungsten, molybdenum, zircon.

I claim:

A chill or die casting of an alloy consisting of from 65% and up to 94% copper, from 2% to 6% silicon, from 3% to 28% zinc, and an appreciable amount of aluminum not more than 2%. 85

- EUGEN VADERS. 

